Block #359,870

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/15/2014, 2:22:20 AM · Difficulty 10.3869 · 6,449,057 confirmations

2CC
Cunningham Chain of the Second Kind

A sequence where each prime is double the previous prime minus one.

Block Header
Block Hash
b0728455b9efecd8c8a1e2b8004908cbdac24367ee4d64972d9deab825ce105c

Height

#359,870

Difficulty

10.386941

Transactions

6

Size

1.31 KB

Version

2

Bits

0a630e8b

Nonce

15,890

Timestamp

1/15/2014, 2:22:20 AM

Confirmations

6,449,057

Merkle Root

c459050a85a055da2835a329fa10543d038c0dd8abe8abff33a20f75406ff9c4
Prime Chain Origin

This is the prime chain origin stored in the block header. It is a composite number (not prime itself) — it equals the first prime in the chain multiplied by a primorial. The origin anchors the entire chain to this specific block.

6.381 × 10¹⁰³(104-digit number)
63814769197144700126…53064289129181388801
Discovered Prime Numbers
p_k = 2^k × origin + 1

These are the actual prime numbers discovered by this block, computed using the verified Primecoin formula. Each number has been independently confirmed to pass the Fermat primality test. Use the FactorDB links to verify any number independently.

1
origin + 1
6.381 × 10¹⁰³(104-digit number)
63814769197144700126…53064289129181388801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.276 × 10¹⁰⁴(105-digit number)
12762953839428940025…06128578258362777601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.552 × 10¹⁰⁴(105-digit number)
25525907678857880050…12257156516725555201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.105 × 10¹⁰⁴(105-digit number)
51051815357715760101…24514313033451110401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.021 × 10¹⁰⁵(106-digit number)
10210363071543152020…49028626066902220801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.042 × 10¹⁰⁵(106-digit number)
20420726143086304040…98057252133804441601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.084 × 10¹⁰⁵(106-digit number)
40841452286172608080…96114504267608883201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
8.168 × 10¹⁰⁵(106-digit number)
81682904572345216161…92229008535217766401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.633 × 10¹⁰⁶(107-digit number)
16336580914469043232…84458017070435532801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.267 × 10¹⁰⁶(107-digit number)
32673161828938086464…68916034140871065601
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 10 consecutive prime numbers forming a Cunningham Chain of the Second Kind. The prime chain origin — the large number shown above — anchors the chain and is divisible by a primorial (the product of small primes), cryptographically tying these prime numbers to this specific block.

★★☆☆☆
Rarity
UncommonChain length 10

Roughly 1 in 100 blocks. Solid but expected in a healthy network.

How Primecoin's Proof-of-Work Constructs These Primes

Primecoin stores a value called the prime chain origin in each block. The miner found a large integer such that when divided by a primorial (the product of small primes: 2 × 3 × 5 × 7 × …), the result is the first prime in the chain. The origin is deliberately divisible by this primorial — that divisibility is part of the proof.

Prime Chain Origin = First Prime × Primorial (2·3·5·7·11·…)
Source: Primecoin prime.cpp — CheckPrimeProofOfWork()

This is why the origin has many small prime factors — those factors are the primorial divisor. The chain then extends from the first prime using the 2CC formula:

2CC: p₁ (first prime), p₂ = 2p₁ − 1, p₃ = 2p₂ − 1, …
Circulating Supply:57,715,472 XPM·at block #6,808,926 · updates every 60s
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